Dual polarized horn antenna



Sept. 7, 1965 E. RABURN DUAL POLARIZED HORN ANTENNA Filed Aug. 30, 1956 lilll IIIII I.

INVENTOR.

.LOUIS E. RABURN.

dew/QW- ATTORNEY United States Patent 3,205,499 DUAL POLARIZED HORN ANTENNA Louis E. Raburn, Golf Manor, Cincinnati, Ohio, assignor to Avco Manufacturing Corporation, Cincinnati, Ohio, a corporation of Delaware Filed Aug. 30, 1956, Ser. No. 607,213 4 Claims. (Cl. 343-730) This invention relates to an antenna for transmitting or receiving electromagnetic wave energy, and, more particularly, to an antenna in which two antenna elements .are combined in a novel manner to produce new and useful results.

According to the present invention, two antenna elements, both suited for flush-type mounting, are combined and arranged in such a manner as to permit both to occupy no more space than normally required for only one of the elements. This results in a saving of space which may be of great importance where the mounting space is limited, as in the case of aircraft, and, in addition, certain other unique advantages result from this arrangement as will be more fully understood as the description proceeds. Moreover, it has been found possible to accomplish this superposing of the elements while enabling them to operate independently of one another and without appreciable mutual coupling or undue pattern degradation. Also, due to the cross-polarization of the two elements, and their relatively wide beam width and band width, any desired type of wave polarization can be radiated therefrom or received thereby.

The particular antenna configuration which I have devised to produce these results comprises the combination of a horn and a dipole, the dipole lying at the mouth of the horn and in the plane of the opening so that flushtype mounting of both elements can be obtained. The horn antenna may desirably be provided with a flared enclosure terminating in a slot or opening, and the dipole element may be situated in the plane of the slot and disposed lengthwise thereof so as to cause the energy radiated by the two elements to be perpendicularly polarized. The band width characteristic of the dipole element may be increased by employing .a fan-type dipole which has been found not to interfere with the field pattern of the horn element. It is thereby possible to match the band width characteristic of the dipole element with that of the horn element and, since both elements have essentially the same dire'ctivity pattern, it is possible to provide any desired type of polarization, whether linear, elliptical, or circular. The antenna may be mounted on any sort of ground surface, whether it be flat or curved, and it may be used without any ground plane or other external mounting surface if desired.

Accordingly, it is an object of the present invention to provide an antenna configuration which combines a horn and a dipole in the same space.

Another object of the invention is to provide an antenna which is constituted of two flush antenna elements having a common aperture and housing.

Another object of my invention is to provide an antenna which is comprised of two antenna elements which operate independently f one another and without mutual coupling or pattern degradation even though they are mounted in a common aperture and housing.

Another object of the invention is to provide a flushtype antenna which is capable of transmitting or receiving any type of polarized wave.

Another object of the invention is to provide a crosspolarized antenna in which a fan dipole is disposed longitudinally in the aperture of a flared horn.

With these and other objects in view which will become apparent from the following description, the invention includes certain novel features of construction and tangular configuration.

7 3,205,499 Patented Sept. 7, 1965 combination of parts, the essential elements of which are set forth in the appended claims, and a preferred form or embodiment of which will hereinafter be described with reference to the drawings which accompany and form a part of this specification.

in the drawings:

FIG. 1 is a perspective view of an antenna which incorporates the teachings of my invention.

FIG. 2 is a cross-section view taken along the line 22 in FIG. 1.

FIG. 3 is a cross-sectional View along the line 33 in FIG. 1.

FIG. 4 is a partially sectioned detail view of the coaxial cable connector shown in FIG. 3.

Similar reference characters designate similar or identical elements and portions throughout the different views of the drawings.

One possible form or embodiment of the invention is shown in the accompanying drawings wherein the horn antenna is shown to include a housing or enclosure 10 which is rectangular in shape and includes two pairs of side walls 11 and 12 which together form a tubular enclosure which provides a housing for the antenna. One end of the housing is closed by an end plate 13 while the other end is terminated in a slot or opening '14 of rec- As best shown in FIG. 3, the sidewalls 11 are flared outwardly in the vicinity of the slot 14 to etfect the desired termination of the housing in the slot. As shown in FIG. 2, the sidewalls 12 may be terminated in the slot without any flare.

The sidewalls 11 and 12 are provided in the plane of the slot 14 with a mounting flange 15 by which the an tenna may be fastened to a ground plane or Wall 16. The dipole element 17 may likewise be supported by flanges 15 in the plane of the slot 14, this support being effected by a sheet of dielectric material 18 on which the radiating elements 19 of the dipole are printed or otherwise formed as shown in FIGS. 1 and 2. It is to be noted that the elements 19 of the dipole extend in the direction of the length of the slot 14 so as to provide cross-polarization of the horn and the dipole. That is, as viewed in FIG. 1, the dipole will be polarized vertically whereas the horn will be polarized horizontally. The dipole is preferably of the fan type as shown in FIG. 1.

The manner of feeding the horn antenna and the dipole is optional; however, in the present instance, both are shown to be fed by coaxial cables 25 and 26 (FIG. 1). In the case of the dipole 17, the coaxial cable, which is unbalanced to ground, is connected through a balun 28 (FIG. 2) to a balanced line comprised of conductors 29 and 30 which are terminated in the elements 19 of the dipole. The inner conductor 31 of the coaxial cable 25 is connected either directly, or through a crystal detector 32, to the inner conductor 33 of the balun. The condoctor 33 is surrounded by a metal skirt 34 having a length equal to a quarter wave length. The distal end of the skirt is connected to the conductor 29. The inner conductor 33 is joined at 35 to the end of a post 36 formed of conductive material which terminates in a plug 37. The plug is of a suitable length to provide a quarter wave spacing between its inner end 38 and the distal end of the skirt 34. A screw 39 passing through the side wall 12 of the housing secures the plug thereto and provides support for the end of the balun. The skirt 34 and post 36 are enclosed within a metallic sleeve 40 which is provided with an aperture 41 through which the conductors 29 and 30 pass out to the dipole. The end of the sleeve 40 adjacent to the coaxial cable connection 43 is fitted with a plug 42 which is apertured to receive the inner conductor 33 and which provides support for the skirt 34. The length of the plug 42 is such as to enable the quarter Wave skirt 34 to be suitably located within the sleeve 3 with its distal end lying adjacent to the aperture 41 and the conductor 29. The outer conductor of the coaxial cable 25 is, of course, electrically connected, through the connector 43, with the skirt 34, and the inner conductor 31 is connected, as shown, to the conductor 30.

The feed for the horn antenna is through a post 50 (FIG. 3) which terminates on the side wall 11 lying opposite the coaxial cable 26, the end of the post being brazed or soldered to the side wall. The post is electrically connected with inner conductor 52 (FIG. 4) of the coaxial cable 26 either directly or through a crystaldetector 53. The outer conductor of the coaxial cable is connected through the connector 51 with the side wall of the antenna housing.

When the apparatus is to be used for transmitting, the crystal detectors 32 and 53 should, of course, be omitted and the inner conductors 31 and 52 of the coaxial cables 25 and 26, respectively, connected directly to the conductor 33 and post 50, respectively. However, when the antenna is used for receiving purposes, it may be found desirable to utilize the crystal detectors 32 and 53 to convert the received signals into D.-C. pulses. By the use of the crystal detectors with the cross-polarized antenna elements of the present invention, it is possible to receive signals of any conceivable type of polarization and obtain a significant response therefrom.

While the apparatus shown herein is particularly suitable for flush mounting in a wall or a panel, the unit is not restricted to such type of mounting and -may be used without any supporting Wall at all, as shown in FIG. 1, since it comprises a self-contained unit enclosed Within its own housing 10.

Although I have described my invention in connection with one possible form or embodiment thereof and having used certain specific terms and language herein, it is to be understood that the present disclosure is illustrative rather than restrictive and that changes and modifications may be resorted to without departing from the spirit of my invention or the scope of the claims which follow.

I claim:

1. Antenna apparatus for simultaneously receiving or transmitting two cross-polarized waves comprising: a tubular conductive enclosure closed at one end and terminated at the other end by an elongated, rectangular opening; means for feeding signal energy to said enclosure to energize said opening and thereby radiate a first polarized wave; means for energizing said opening with a second wave polarized in a plane perpendicular to said first wave, said means comprising a dipole antenna mounted in the plane of said opening; and means for feeding signal energy to said dipole elements, whereby said second wave polarized perpendicular to said first wave will be radiated from said opening.

2. The invention as defined in claim 1, wherein said enclosure flares in the vicinity of said opening.

3. The invention as defined in claim 1, wherein said means for mounting said dipole antenna comprises a wall of dielectric material mounted on said enclosure to close said opening, and wherein said dipole antenna is secured to said wall.

4. The invention as defined in claim 3, wherein said dipole antenna is printed on said wall.

References Cited by the Examiner UNITED STATES PATENTS 2,460,286 2/49 7 Hansen et al 343767 2,656,463 10/53 Woodward 343795 2,673,931 3/54 Stevens 343795 2,724,772 11/55 Bridges 343767 X 2,760,192 8/56 Shanklin 343727 2,820,965 1/58 Sichak 343756 2,863,145 12/58 Turner 343767 FOREIGN PATENTS 409,116 2/45 Italy. I

HERMAN KARL SAALBACH, Primary Examiner.

NORMAN H. EVANS, CHESTER L. JUSTUS, FRED- ERICK M. STRADER, Examiners. 

1. ANTENNA APPARATUS FOR SIMULTANEOUSLY RECEIVING OR TRANSMITTING TWO CROSS-POLARIZED WAVES COMPRISING: A TUBULAR CNDUCTIVE ENCLOSURE CLOSED AT ONE END AND TERMINATED AT THE OTHER END BY AN ELONGATED, RECTANGULAR OPENING; MEANS FOR FEEDING SIGNAL ENERGY TO SAID ENCLOSURE TO ENERGIZE SAID OPENING AND THEREBY RADIATE A FIRST POLARIZED WAVE; MEANS FOR ENERGIZING SAID OPENING WITH A SECOND WAVE POLARIZED IN A PLANE PERPENDICULAR TO SAID FIRST WAVE, SAID MEANS COMPRISING A DIPOLE ANTENNA MOUNTED IN THE PLANE OF SAID OPENING; AND MEANS FOR FEEDING SIGNAL ENERGY TO SAID DIPOLE ELEMENTS, WHEREBY SAID SECOND WAVE POLARIZED PERPENDICULAR TO SAID FIRST WAVE WILL BE RADIATED FROM SAID OPENING. 